1. Field of the Invention
The invention relates generally to wireless networks, and more particularly to the delivery of location-based services in an intra-building environment through the use of short-range wireless technology.
2. Description of the Prior Art
Short-range wireless technologies such as 802.11, Bluetooth, HomeRF, and others are being rapidly deployed to allow mobile devices to connect with existing intra-building wired Local Area Networks (LANs). To enable this connectivity, wireless access points are being developed by various manufacturers. An example of such an access point is the Aironet 340 access point (an 802.11 type access point) manufactured by Cisco Systems, Inc. of San Jose, Calif. Another example is the AXIS 9010 access point (a Bluetooth type access point) manufactured by Axis Corporation of Lund, Sweden. Short-range wireless access points deliver connectivity over a small radius, i.e., a radius that is typically 100 meters or less.
At the same time, a wide variety of location-based services have been developed over wide-area cellular networks. These services include: (1) emergency location services (commonly referred to as “E-911” services); (2) consumer information services, such as locating the nearest restaurant, gas station or parking spot; and (3) mapping services for determining the optimal route to a particular destination. These location-based services are implemented by determining the user's location through queries to a cellular base station or Home Location Register (HLR) at the cellular service provider. Alternatively, implementation is achieved via triangulation of critically located points obtained through multiple base stations. The resolution of such location determinations is typically on the order of a few hundred meters.
Cellular service coverage is often limited in intra-building environments, making existing location-based services, and indeed wide-area services, generally inaccessible. Moreover, the granularity of location information, which is hundreds of meters, is too coarse to be useful for intra-building location-based services. There are myriad types of intra-building location-based services. By way of example, these services may include: (1) locating the nearest computer printer or the nearest projector; (2) locating the nearest person meeting a particular characteristic, such as the nearest cardiologist in a hospital environment; and (3) locating the nearest restroom. For such intra-building requests, users require location-based services having the capability of providing answers within a granularity on the order of tens of meters. Clearly, existing wide-area location-based services are insufficient for this task.
Therefore, what is needed is a system and method for delivering location-based services in an intra-building environment. The method must provide reliable coverage within the building and must deliver service with a fine level of granularity.